Commercial fishermen catch and process tons of fish a day. Many fishermen have complex, highly automated processing equipment which dress the fish and produce numerous different commercial products for commercial retailers, such as restaurant chains or grocery stores. Such equipment is highly specialized to perform a specific task, such as cutting the heads and tails off, filleting, deboning and skinning, etc. One of the reasons such equipment must be tailored to specific tasks is the large variety of shapes and sizes of fish processed, including pollock, salmon, trout, sole, cod. etc.
To reduce overall processing costs and to improve quality, some commercial fishing vessels include processing equipment and freezers located directly on the ships. As the fish are caught, they are immediately processed and frozen, substantially improving the quality of the final product. This also allows the vessels to remain at sea for long periods of time without transporting the fish to a shore-based processing facility. Most of the processing equipment is large, complex, and expensive. It is difficult and expensive to remove the processing equipment from the vessel and replace it with new processing equipment.
Because of the expense associated with exchanging the processing equipment, including vessel down time, most commercial processing ships are intended to catch and process specific types of fish. As an example, the vessel may be fitted with processing equipment designed to process generally oval fish having a relatively thick cross section, such as pollock or salmon, or generally flat fish having a relatively thin cross section, such as sole. Due to the natural migration of fish, and various fishing laws, individual types of fish are caught and processed during limited parts of the year. Therefore, vessels having equipment capable of processing only one type of fish sit idle during part of the year. If the processing equipment could be readily exchanged or adapted to process both oval fish, such as pollock or salmon, and flat fish, such as sole, the vessels could be operated over a larger part of the year. This would, in turn, reduce the amount of down time and associated expense for the vessels.
One manufacturer of fish processing equipment is Baader GmbH & Co. KG, Lubeck, Germany ("Baader"). One of the many fish processing machines produced by Baader is the Baader 182 . The Baader 182 is designed to process pollock and salmon-shaped fish and includes a conveyor having a plurality of fish holders mounted along the length of the conveyor. Each fish holder includes a recess configured to receive a pollock. While operating, a worker removes fish from a fish hopper located next to the conveyor and places an individual pollock in the recess of each fish holder. The conveyor subsequently moves the fish holders and pollock along the length of the conveyor into contact with rotating blades that cut both the head and the tail of the pollock off The body of the pollock is then carried to additional equipment that cuts the pollock into fillets and removes the bones and skin.
The Baader 182 works well with fish having an oval cross section, such as pollock, but does not allow other types of fish to be processed. The Baader 182 is particularly unsuitable for processing fish with a relative flat cross section, such as sole. The fish holders used on the Baader 182 are not capable of holding such fish during processing.
In addition to having a relatively thin cross section, the body of a sole also has a lower length to height ratio than pollock or salmon, i.e., the body is more oval-shaped when viewed from the side. The shape of the sole presents additional problems in processing. The orientation of the body of the sole must be carefully maintained to ensure that the head and tail are removed in such a way as to leave the majority of the body intact. If the orientation of the sole is improper, the sole tends to be cut at angles which either remove too much of the body or leave parts of the head or tail. Therefore it is important that the sole or similarly-shaped fish be carefully centered within the fish holders before being brought into contact with the cutting knives.
Because the fishing seasons for pollock, salmon, sole, or similarly-shaped fish are at different times of the year, it would be beneficial if the processing equipment could process both types of fish. One of the goals of the present invention is to allow current processing equipment to handle both fish having a relatively thick cross section, such as pollock and salmon, and fish having a thin cross section, such as sole. Another goal of the present invention is to allow processing equipment to center flat fish within the fish holders while holding the fish, such that the head and tail may be removed. An additional goal of the present invention is to allow Baader 182 or other processing equipment to be modified from a pollock or similar fish processing configuration to sole or other flat fish processing configuration without substantial difficulty or expense, thus allowing the equipment and vessels to process multiple types of fish.